The IP Multi-Media Subsystem (IMS) architecture is a unified architecture that supports a wide range of services enabled by the flexibility of Session Initiation Protocol (SIP). IMS is defined by certain 3GPP and 3GPP2 standards (such as 3GPP TS 22.228, TS 23.218, TS 23.228, TS 24.228, TS 24.229, TS 29.228, TS 29.229, TS 29.328 and TS 23.320 Releases 5-7).
In order to leverage the investments in the IMS infrastructure new types of multi-media services are developed. One type of IMS-enabled services regards the so-called combinational services also referred to as blended or composite services, which combine services of various platforms and make use of the functionalities and capabilities of various platforms and distribution techniques (e.g. phone, multicast, broadcast, television/video, content-on-demand etc.). A type of IMS-enabled services regards interactive multi-media services wherein the end-user is an active participant instead of a passive viewer.
Further enhancements of this type of IMS-enabled services may include an end-user and/or the network operator to compose a multimedia service from different multimedia streams. For example an end-user may compose a personalized multimedia service by enriching a main service, for example a TV broadcast (BC) with personally selected multi-media content, such as content-on-demand (CoD), user-generated content (UCG), etc., originating from different sources in the network.
An example of an implementation of such a personalized TV service in a state-of-the-art architecture is described in the article of Rauschenbacher et. al, “A scalable interactive TV service supporting synchronized delivery over broadcast and broadcast networks”, a Fraunhofer white paper of May 14, 2004. In this document a system is described wherein the main content stream is transported over a DVB network in the form of a broadcast channel to a Home Media Server at the end-user location. In addition, multiple additional content streams may be transported via a broadband IP network to the Home Media Server. At the Home Media Server, these additional content streams may be synchronized with the main content stream and thus presented to the end-user (display) device in a synchronized manner.
One of the disadvantages of the scheme described in Rauschenbacher et. al is that all end-user display equipment needs to be connected directly to the Home Media Server (HMS) for consuming these enriched services. Another disadvantage is that the HMS is a type of equipment of substantial complexity and needs to have a robust design with the necessary processing power to realize the personalized TV service functionality. In short, the prior art only allows the managing of the enriched television experience by the end-user. Information regarding the relation between the different multimedia streams originating from different sources in the network and delivered as separate streams to user equipment only exists at the user equipment (HMS).
An exemplary network architecture, such as an IMS network, more in particular the IMS network elements managing the multimedia services in the IMS network, is however not aware of the fact that these multimedia sessions are used in combination by an end-user to generate a personalized multimedia service. It may however be convenient and/or even be necessary to manipulate the personalized television experience from within the network. For example, it may be convenient to simultaneously pause associated multimedia streams, that together form the personalized television experience, in order to deliver a targeted advertisement or a hurricane warning or other content to the end-user before resuming the personalized television experience. Also, reserving bandwidth in the network for all related streams may also be convenient. Another example whereby the network needs to know which streams are related is the situation of an incoming phone call. If a number of streams relate to a personalized television experience, and a number relate to individual download sessions or to a multimedia recording session on the background, it would be convenient if the network could only pause the streams related to the personalized television experience and not those related to the background download or recording sessions.
In WO2007/101473 describes an example of such a combinational service, where in response to the receipt of a incoming call, a TV program is recorded on a network personal video recording (NPVR) system. In this solution a broadcast stream (channel) is paused upon the receipt of an incoming call and recorded in the network. Upon the user's request, the content may be played from the moment it was paused as a unicast stream. This type of network intervention however only works for a single stream and does not work for the personalized television experience comprising a multiple of streams, possibly originating from different resources, in combination with the presence of one or more other active sessions to the same User Equipment
Within the state-of-the-art IMS architecture, such streams, controlled by and/or originating from different resources would require the set-up of multiple parallel sessions. One session would comprise the stream with the main content and additional sessions for each of the additional streams would comprise the additional content items (for example different subtitles, voice-over, Picture in Picture, etc.). From a network perspective these sessions from the outside would all look the same and no different from other active recording, downloading, gaming, telephony or other sessions. Currently the IMS standards do not allow an end-user and/or the network to compose associated multimedia sessions and to collectively control and/or manage these associated multimedia sessions and their used network resources. Hence, there is a desire in the prior art for methods and systems for managing associated sessions in a network.